Which of these numbers is composite? ${2,\ 5,\ 29,\ 43,\ 57}$
Explanation: A composite number is a number that has more than two factors (including 1 and itself). 2, 5, 29, and 43 each have only two factors. The factors of 57 are 1, 3, 19, and 57. Thus, 57 is the composite number.